1. Field of the Invention
The present invention is generally in the field of electronic circuits and systems. More specifically, the present invention is in the field of communications circuits and systems.
2. Background Art
In the field of wireless communications, 60 GHz technology pursues very high throughput in short-range wireless data transmissions, making possible, for example, real-time uncompressed HD video and audio transfers over wireless data networks. To enable this inherent high-speed data transfer, the 60 GHz standard explicitly defines a requirement called a Traffic Specification (TSPEC) for handling and allocating timeslots for data transfer between high-speed devices. The TSPEC may specify an allocation period over which the allocation repeats, a minimum allocation time and a maximum allocation time for each high-speed data transfer, with each complete data transfer collectively called a traffic stream. Each traffic stream is further comprised of one or more individual timeframes during which data is transferred, called service periods. Typically, there are two types of service periods: 1) pseudo-static and 2) non-pseudo static. Pseudo-static service periods recur at the same target transmission time within an interval, called a beacon interval, regardless of whether the pseudo-static service periods occur in successive beacon intervals or not, whereas non-pseudo static service periods are not required to recur at the same target transmission time within beacon intervals.
In a conventional 60 GHz data technology system a traffic stream is established between a Requesting Device and a Control Device, or unconventionally between two Requesting Devices. A Requesting Device sends a data request carrying a TSPEC, which defines the timing and traffic requirements of the data request. This data request is received by the Control Device. The Control Device determines whether to admit the data request and if admitted, the Control Device may then allocate one or more service periods and announce the service period allocations comprising the traffic stream to the one or more Requesting Devices.
Conventional service period scheduling approaches have traditionally degraded the efficiency of time usage in the system during data transmission in high-speed devices. FIG. 1 shows an exemplary timing diagram representative of a conventional method for scheduling short-range wireless data transmissions. FIG. 1 shows a plurality of fixed-length beacon intervals, each including a length-varying non-data transfer time (non-DTT) period 101 located at the beginning of respective beacon intervals, during which no data may be transferred.
According to this conventional scheduling approach, for example, the Control Device may receive multiple data requests carrying TSPEC1, TSPEC2, TSPEC3, TSPEC4, and TSPEC5, respectively, in time order. In this conventional scheduling approach time slots are allocated for the maximum allocation needed to transfer the requested data in each service period as soon as the Control Device admits a TSPEC. Thus, the TSPEC 1 service period 110 is allocated to beacon interval 1 adjacent the non-DTT period 101 and the TSPEC2 service period 120 is then allocated to beacon interval 1 adjacent TSPEC1 service period 110. However, when the Control Device receives and admits TSPEC3 service period 130, which is pseudo-static having a period of one beacon interval, insufficient timeslots are available in beacon interval 1 to allocate the TSPEC3 service period 130. Thus, the Control Device is forced to allocate the first TSPEC3 service period 130 at the end of beacon interval 2, rather than beacon interval 1 and, because it recurs every beacon interval, to the end of each of beacon intervals 3-8 as well, for example.
Moreover, according to a conventional scheduling approach, the Control Device might allocate the pseudo-static allocations of TSPEC4 service period 140, having a period of two beacon intervals, to every other beacon interval starting with beacon interval 2, as shown in FIG. 1. As can be seen, this inefficient allocation creates fragments of unusable timeslots between non-DTT periods 101 and TSPEC4 service periods 140 in beacon intervals 2 and 4. When the Control Device receives TSPEC5, the conventional scheduling algorithm cannot allocate its service period 150 to beacon interval 2, as shown by the “X”, and is forced to allocate it to beacon interval 3 since the conventional scheduling algorithm allocates a service period for a particular request for data all at once and immediately upon admission. Therefore, the conventional scheduling approach tends to create unnecessary fragments of unusable timeslots in beacons 2 and 4, and may fail the required allocation for TSPEC3 service period 130 in beacon interval 1, for example, as indicated in FIG. 1.
Thus, there is a need to overcome the drawbacks and deficiencies in the art by providing a service period scheduling solution enabling more efficient allocation of data requests to each beacon interval, and designed to avoid failures in allocation of critical data.